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Bug 136891

Summary: 64-bit PPC GDB can't single step out of a signal handler
Product: Red Hat Enterprise Linux 3 Reporter: Andrew Cagney <cagney>
Component: gdbAssignee: Andrew Cagney <cagney>
Status: CLOSED ERRATA QA Contact: Jay Turner <jturner>
Severity: medium Docs Contact:
Priority: medium    
Version: 3.0CC: cagney, ezannoni, jjohnstn, srevivo
Target Milestone: ---   
Target Release: ---   
Hardware: powerpc   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2004-12-21 19:37:21 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On: 108886    
Bug Blocks: 117972, 146413    

Description Andrew Cagney 2004-10-22 20:45:46 UTC 
In the function epilogue, where the dynamic chain (of SP's) has been
torn down, GDB gets confused: it thinks it needs to run down one level
of the SP chain (to get the frame ID's stack address) when it doesn't.
 This, in turn, leads to wrong saved registers being saved, ...

In the case of single-stepping out of a signal handler and into a
signal trampoline, things get especially bad as the
signal-trampoline's frame doesn't actually have a valid SP chain.  It
leads to a bad memory access and that leads to a failed step.

The CFI information, if working, would fix this.
Comment 1 Andrew Cagney 2004-11-10 22:58:24 UTC 
GDB version:
  GNU gdb Red Hat Linux (6.1post-1.20040607.50rh)
Includes CFI for PPC and the test (sigstep.exp) passes.

Andrew
Comment 2 John Flanagan 2004-12-21 19:37:21 UTC 
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on the solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.

http://rhn.redhat.com/errata/RHBA-2004-561.html